Wire harness



Oct. 20, 1942. E R HANSON 2,299,140

WIRE HARNESS Filed June 28, 1939 2 Sheets-Sheet 1 fmesf ff Human ATTORNEY Oct. 20, 1942. E. R. HANSON 2,299,140

WIRE HARNES 5 Filed June 28, 1939 2 Sheets-Sheet 2 Fig. 5.

lNVENTO F! [Fr/7252 R. Hanson ATTORNEY Patented Oct. 20, 1942 WIRE HARNESS Ernest R. Hanson, Bloomfield, N. 1., assignor, by

mesne assignments, to Union Carbide and Carbon Corporation, New York, N. Y., a. corporation of New York Application June 28, 1939,, Serial No. 281,503

3 Claims.

This invention relates to wire bundle and harness constructions and to coveringsfor such harnesses. The general object of the invention is to improve such constructions in this and similar arts.

Wire harnesses are used'in many industries, familiar instances being the harnesses used on ships, automobiles, aircraft, and radio sets. The use of the wire harnesses on automobiles will serve to illustrate the invention. In this use a wire bundle is frequently located in the engine compartment on the front of the dashboard under the hood and contains the wires for the various circuit. From the main bundle, wire or sub-bundles (the so-called legs) are taken off at intervals for connection to the various switches, the lights, generator, battery, battery relay, ignition coil, etc. Thus the size of the Wire bundle changes wherever a leg joins the bundle.

Heretofore the wires of the harness have been held together by a braided covering, the diameter of which has necessarily changed wherever a leg joins the bundle. The braiding of such a covering on the harness leaves much to be desired from a manufacturing point of view. The braiding machines are extremely slow and much time is lost in the braiding process whenever the covering has to be braided at the juncture of a leg with the main bundle. The braiding machines are also extremely noisy and their use is a very definite occupational hazard so far as the hearing and nervous system of the workers is concerned. Moreover, the wires within the bundles are merely held together by the covering and are given no protection from the elements unless the harness is varnished which is costly in the use of materials and labor as well as in the time and space required to dry the varnish, the health hazard of the fumes from the varnish solvents, the fire hazard and the fact that substantially all of the contacts have to be inspected and cleaned after the varnish operation. Furthermore, the usual varnish solvents tend to destroy the insulation on the individual wires and under the conditions of use, the usual varnishes age very quickly, becoming porous and powdery and otherwise deteriorating so that they afford substantially no protection.

For the purpose of explaining the invention, reference may be had to the accompanying drawings in which Fig. 1 is a diagrammatic plan view of a typical harness and Figs. 2 to 9 inclusive are enlarged sections of the correspondingly numbered lines of Fig. 1.

In accordance with the present invention the previously mentioned diillculties are overcome by wrapping the wire bundlesdesignated generally at ID with tapes I2 of the character hereinafter described. By the use of these tapes the diameter of the covering may easily be changed wherever a leg I4 joins the main bundle and the juncture I6 may also be covered and protected quite thoroughly. Tape wrapping machines are very quiet as compared with braiding machines and consequently there is less occupational hazard. The tape l2 used may be relatively wide, for instance one-half to one inch or more and this, combined with the fact that a given length of wire can be covered by taping much more quickly than by braiding, decreases the operating costs of covering the bundles. The tape herein described is not only flexible but preferably has stretch and elastic recovery so that it may be applied to the wire bundles under suflicient tension to stretch it to the desired extent and thereafter, particularly if the harness is manipulated slightly, for instance when it is being placed in position on the automobile, the wires 18 in the bundle are compacted and drawn together. The tape should be sufficiently thick that it can withstand considerable stretching and tension when applied yet contract so that it draws together the wires in the bundle afterthe bundle is wrapped. The harnesses differ from cables in that a cable is very carefully designed and made with accurately positioned and insulated conductors, filled filler spaces etc. to give a long smoothly surfaced cable while in a harness the wires are assembled in odd shaped bundles as illustrated in Figs. 2-9 with the number of wires changing as the legs join the bundles and the wires carry a rather low voltage. It is important in a harness that the wires be compacted and that the tape be thick enough to do this as well as thick enough to withstand the mechanical stresses due to water drops driven against it or careless handling or striking since, on harnesses, the tape I2 is the outer covering with no lead or cloth sheath or other protection. However, th'e tape should not be too thick, as this unnecessarily increases the cost and has a tendency to make the junctures of the legs with the main bundle too bulky; also if the tape is too thick, difiiculty may be experienced in taping the junctures and forming a smooth juncture covering. The surface of the tape may be and preferably is inherently slightly adhesive or pressure sensitive so that two contacting surfaces thereof will adhere somewhat but only with such tenacity that they can easily be separated by a direct backward or upward pull such as is given in a taping machine. The surfaces are not sticky and will not adhere to a persons hands. Thus paper or other separating media are unnecessary in a roll of the tape and the tape runs freely and cleanly through the taping machine. The adherence or pressure sensitiveness, however, particularly in conjunction with the elastic recovery, enables the overlapping edges of the tape spirals to seal and keep water, dust, acids, alkalis, and corrosive materials out of the bundles, as the material from which the tape is made is impervious to these.

The material from which the preferred tape is made is electrically insulating and fire resistant but will soften somewhat and flow together at high temperatures, for instance between 130 C. and 160 C. and use is made of this characteristic in manufacturing the wire bundles; but none of the characteristics of the tape change to any appreciable degree under the temperatures produced within the hood of an automobile during the operation of the engine. In the preferred composition the elasticity and elastic recovery of the material are not lost by heating to temperatures between 130 C. and 160 C. but are retained and in consequence a taped harness may be heated to weld together the overlapping edges of the tape and yet the tape, both while hot and upon cooling, still has the tendency to draw together the wires in the bundle. I

The tape comprises a resinous vinyl halide, or a mixture of polymers of halide and acetate but preferably a copolymer of vinyl chloride and vinyl acetate, and also preferably includes a plasticizer, a lubricant and a stabilizing agent together with such pigments, dyes, flllers etc. as are desired. The vinyl resins preferably have an extremely high molecular weight, for instance a molecular weight of 18,000 to 30,000. The preferred tapes herein disclosed are extremely tough and have a high tensile strength as they must have for this type of work where the harnesses must be made with great speed, at a low cost, and in large quantities. The vinyl halides include the esters of bromine, fluorine, iodine and chlorine, the latter being preferred because of the availability and low cost of chlorine. The organic esters include the esters of the lower aliphatic acids for instance acetic, propionic, butyric, valeric and caproic acids.

The plasticizer (or mixture of plasticizers) which is preferably flame resistant, may include a material for instance tricresyl phosphate, dibutyl or other higher alcoholic esters of phthalic acid or anhydride, triphenyl phosphate, triethylene glycol dioctoate or a polyhydric alcohol which is flexible at low temperatures.

The lubricants may be mineral oils or greases,

' fatty acids or their salts, for instance stearic acid or its calcium or lead or aluminum salts, waxes for instance the vegetable or mineral waxes such as camauba, paraflin, ozokerite, ceresin waxes, chlorinated naphthalene or derivatives etc., or mixtures thereof.

The stabilizing agents may be calcium or lead salts (either organic or inorganic), for instance calcium or lead stearate or carbonate, or calcium or lead oxides, for instance lime or litharge.

The pigments may, in general, be the paint pigments or dyes, except those which are found to be decomposition catalysts for the chlorinated vinyl compounds for instance materials containing zinc or iron.

The fillers may be any suitable material, for instance diatomaceous earth, titanium oxide, barytes, whiting, Paris white, talc, mica, asbestos, powdered glass, etc. The fillers are preferably capable of withstanding high temperatures and may also function 'as pigments.

In general, the tape compositions using the above materials include for every 100 parts of vinyl resin, 25 to 40 parts of plasticizer, 1 to 5 parts of lubricant, 1 to 5 parts of stabilizing agent and, if fillers and coloring materials are used, up to 20 parts of filler and pigments up to about 5% if required to produce the correct color. The flow points of these compositions are over C. as determined by the A. S. T. M. ball and ring test and they should withstand temperatures of 100 C. for at least a month without decomposition. The compositions also should not crack at low temperatures, for instance 18 C. below zero, that is temperatureswhich might be encountered by automobiles manufactured in a cold climate.

In making the tape the ingredients may be mixed and kneaded until homogeneous. The thoroughly homogeneous mass may then be placed in the reservoir of an extruding machine and extruded into tape-form. If necessary, as is usually the case, the mixed mass may be softened for extrusion purposes merely by heat or by the addition of a solvent or both. Also the tapes may be made by rolling or calendering the mass to a wide sheet of the desired thickness which is then cut into the proper width for the desired tapes. The tapes may also be made by casting the material either in the desired width or in a wide sheet and cutting to the desired width.

The following examples are given by way of further explanation although it is to be understood that they are merely for illustrative purposes and the invention is not to be strictly limited thereto.

Example I .53 parts of a vinyl resin copolymer having approximately 95% vinyl chloride and 5% vinyl acetate and a molecular weight of 20,000 to 30,000 are mixed with 40 parts triethylene glycol dioctoate and 2 parts of white petroleum mineral oil and 5 parts of lead stearate. For a black tape 1 part of a suitable carbon black may be added. These materials are thoroughly kneaded, usually for about an hour. The mass is then placed in any suitable extruding or casting machine and the extruded or cast tape is led from the extruding nozzle onto a roll. If cooled sufficiently between the extruding nozzle and the roll, the layers on the roll will not permanently adhere to each other even though a separator is omitted. The tapes may also be made from calendered sheets as previously explained.

Example II.--60 parts of a copolymer having 90% vinyl chloride and 10% vinyl acetate and a molecular weight of 18,000 to 24,000 are mixed with about 35 parts of tricresyl phosphate, 2 parts of carnauba wax, 3 parts of calcium stearate and 10 parts of talc. The mass may be treated as in Example I.

Example III.The ingredients and treatment of Example II may be used adding about part of Sudan red which is sufficient to dye the amount of material to a brilliant red.

Example IV.--The mix and treatment of Example I may be followed (omitting the carbon black) adding 1 part of chrome green pigment to obtain a green color. 7

Example V.-70 parts of a vinyl resin copolymer containing about 86%-87% of vinyl chloride and 13%-14% vinyl acetate and a molecular weight of 10,000 to 1%,000, 26 parts of an ester of a polyhydric alcohol, for instance the ethyl butyrate of a polyethylene glycol, 1 part of stearic acid, and 3 parts of basic lead carbonate are mixed and treated as in Example I.

The molecular weights given are calculated by means of Staudingers formula from dilute solutions of the resins.

In making the tape, the material may be softened merely by heat or by the addition of a solvent, or both, and extruded or calendered and cut into tape form or cast, as previously described. A tape with resin of approximately 6 to 10 mils. in thickness is highly satisfactory for harness use. Such a tape has the characteristics herein described. The resin may, however, be as thin as 3 mils. and it is preferred that it does not exceed 30 mils. If the resin be substantially thinner than 3 mils, it is not strong enough to give the desired compression of the wires after the harness is wrapped and as the harness should have only one wrapping of tape for low cost and to prevent buckling, a covering which is built-up of several layers is undesirable. On the other hand a resin strip which is substantially over 30 mils. in thickness is wasteful of material and it is diflicult to make, on a taping machine, a properly taped juncture of a leg with the main bundle. The tape is preferably made from the above mix without the incorporation of any reinforcement and one of the features of the invention is that it can be so made and used as an all-resin tape. If a textile be used it is important that it be one which does not materially interfere with elastic recovery because when the tape is applied to the harness, there are places, for instance where the legs are joined, where a tape is given irregular convolutions and the usual tapes have a tendency to buckle and form wavy or puckered edges on the short side of the turn, but when the present tape is applied under tension, the elastic recovery and the fact that one edge can stretch without the other, causes the tape to bind tightly.

A tape made of the previously described materials is a decided improvement over a natural rubber tape. The elastic and the elastic recovery properties of such rubber as could be used for the purposes herein described differ between its condition when applied and its condition after being subjected to the heat of the engine, whereas these properties do not materially change in the materials described herein. Also rubber is not very resistant to acids and alkalis nor is it flame resistant nor is it resistant to gasoline and oil but deteriorates rather quickly in contact with these substances and due oxidation, particularly in the presence of heat.

Other features of the tapes made from the hereinbefore disclosed materials are that the tensile strength is greater than rubber, a tape say 10 mils. thick requires more force to stretch it a given distance than does rubber, the compressive force it exerts on the strands in the bundle is greater than rubber and yet its elastic recovery, while substantially complete, is delayed or retarded; comparing the action with that of rubber, a rubber band or tape requires relatively little force to stretch it say 10% of its original length, and will,'if stretched, immediately snap back to its original position upon release but with the compositions disclosed hereinbefore a much greater force is required to stretch the material 10% of its original length, the recovery is progressively slower as the tape approaches the position it had before being stretched and the tenslon and compressive force is much greater than in the case of rubber. This is a distinct advan-' tage in the manufacture of harnesses as the difference in power requirements to apply a high tension tape or a low tension tape is negligible but the fact that the full compressive force of the herein described tapes is not exerted at the moment the tape is applied but is exerted gradually, although the compressive force is presistent, enables the wires of the harness to adjust themselves into a compact bundle as the harness is manipulated first in the taping machine and later when the harness is being handled, for instance when it is removed from the taping machine, transported and handled prior to and after being treated in the sealing oven, applied to the car, etc.

For the harness uses disclosed herein, the mechanical and chemical rather than the electrical properties of the compositions are deemed important as the voltages carried by harness wires on cars is usually not much over 12 v., but the tape must not deteriorate chemically under operating conditions. It must be easily applicable to'the bundle and should be tough and not soften sufiiciently to become weak or run under operating' conditions. Although a straight vinyl chloride may be used as the base for the compositions, it is preferred to use a copolymer of a vinyl halide and vinyl acetate containing not less than vinyl chloride to 20% vinyl acetate.

The previously disclosed materials, namely vinyl chloride, the joint polymers of vinyl chloride and vinyl acetate, and the mixtures of polymers of vinyl chloride and vinyl acetate are preferred for harness tapes for the reasons previous ly described.

The harnesses Ill are groups of non-continuous electrical conductors l8 frequently of a length less than fifty feet unless, for instance on a motor boat a somewhat longer leg wire may be required. On an automobile the main bundle may be five or ten feet long with leg wires 14 which are longer and extend to the head and tail lights. In the main bundle and also on the legs if desired, the wires are bound together and the individual wires join the group at any interval depending upon their ultimate destination. In making the harness the tape is merely placed under tension by stretching sufliciently at the wrapping machine, wrapped around the bundle of wires, starting from one end of the wires and progressing to the other, joining the legs to the main bundle by taking the wires in or off as the case may be and wrapping the junctures. In the preferred construction there is only one wrapping of the tape 12 as a plurality of wrappings is costly and in harnesses there is frequently compacting of the conductors for a period of time after the harness is wrapped; thus if several layers of adherent tape were used the wrapping might buckle as the wires compact. After wrapping the entire assembly may be heat treated, for instance by being passed through an oven. The oven is preferably quite hot being maintained at a temperature from about 180 C. to 200 C. but the bundle is passed through rather quickl for instance in from about 3 minutes to 1 minute, so that the tape is heated sufficiently for the overlapping edges to weld together but the harness is not heated through and the rubber or other insulation on the individual wires is substantially unaifected. A treatment may be effected at C. for 15 minutes but this has a tendency to heat the entire bundle. As a tape only mils. in thickness is sufflciently thick for use on automobile harnesses, it will readily be seen that only a flash heat need be used for sealing and the tape is preferably not heated sufilciently to enable the resinous covering to run orflow away from its point of application. Thus there are no inflammable or injurious fumes, the wire insulation is not harmed, and the contacts 20 do not have to be cleaned. Furthermore, as the material has elastic recovery even when hot, an extremely perfect weld is obtained when the harnesses are heated as previously stated since the tape is under tension while the weld is being made.

When the wire harness is applied to an automobile, the individual wires in the harness are joint polymerization of a vinyl halide with a vinyl ester of a lower aliphatic acid, the resin held firmly together and are protected from gasoline or oil which may be spilled on them and from the hot fumes of these substances. The wires of the harness (together with the lead from the battery to the starter, if the lead is wrapped) are also protected from acid fumes which may be generated by batteries, as well as from corrosive substances, for instance calcium chloride, tar and sulphite used to treat roads and which may be thrown onto the wires, alkalis, for instance soap and other washing fluids, and also water, alcohol and other coolants which either leak or vaporize out of the cooling system of the engine. For wire harnesses used on airplanes the same advantages are obtained and particularly on hydroplanes, ships, motor boats or automobiles used on or near salt water where the atmosphere is charged with corrosive chemicals. Radio equipment used in any of these places is subjected to the same general conditions and even in the home is subjected to moisture and to the acid fumes from furnace gases, etc. The fact that the tape covering is permanent and is of itself electrically insulating gives it added advantages on harnesses used as described.

It will thus be seen that the invention is of wide application and it is desired that it be construed as broadly as the following claims, taken in .conjunction with the prior art, may allow.

I claim:

1. A wire harness construction comprising a main bundle of a plurality of unconnected, separately insulated, individual wires, one or more of which is separated from the main bundle at intervals to form an insulated leg wire or wires, and a wrapping of stretched tape over the main bundle and the juncture of the leg wire or wires, serving to draw together the wires in the bundle, said tape comprising a plasticized vinyl resin, said resin being of the group consisting of resinous polymeric vinyl halides, resinous polymeric. vinyl esters of the lower aliphatic acids and 5% being substantially impervious to water, dust, acids,.a1ka1is, gasoline and oil, and being capable of elastic recovery after stretching and, when in tape form, being capable of stretching along one edge without the other to provide a wrapping at said juncture substantially free from puckered edges. r

2. A wire harness construction comprising a main bundle of a plurality of unconnectedseparately insulated, individual wires, one or more of which is separated from the main bundle at intervals to form an insulated leg wire or wires, and a wrapping of stretched tape over the main bundle and the juncture of the leg wire or wires, serving to draw together the wires in the bundle, said tape comprising a plasticized vinyl resin which is a product of the conjoint polymerization of vinyl chloride with vinyl acetate and contains approximately of vinyl acetate and has a molecular weight of approximately 20,000 to 30,000, the resin being substantially impervious to water, dust, acids, alkalis, gasoline and oil, and being capable of elastic recovery after stretching and,

when in tape form, being capable of stretching along one edge without the other to provide a wrapping at said juncture substantially free from puckered edges.

3. Method of manufacturing a wire harness containing a main bundle of a plurality of individual, unconnected, separately insulated wires, one or more of which separate from the main bundle at intervals to form an insulated leg wire' or wires which comprises assembling the wires into the bundle with the wires extending in the same general direction, wrapping the main bundle of wires with a stretched elastic tape capable of elastic recovery after stretching and capable of stretching along one edge without the other and comprising a plasticized vinyl resin, said resin being of the group consisting of resinous polymeric vinyl halides, resinous polymeric vinyl esters of the lower aliphatic acids and a resinous product resulting from the conjoint polymerization of a vinyl halide with a vinyl ester of a lower aliphatic acid, the resin being substantially impervious to water, dust, acids, alkalis, gasoline and oil, while leaving the filler spaces open. taking one or more of the wires from the main bundle at intervals to provide a leg wire or wires, wrapping the juncture of the leg wire or wires and the main bundle and heating the wrapped harness to a temperature and for a period of time sufiicient to seal the wrapping but insuflicient to deteriorate the insulation on the wires.

ERNEST R. HANSON.

% of vinyl chloride ,n 

